High speed sheet feeding apparatus

ABSTRACT

A high speed sheet feeding apparatus in which the lowermost sheet of a stack is propelled from the stack by a rotating perforate cylindrical member connected to a source of vacuum. A pawl actuated by an adjustable cam governs the amount of rotation of the cylindrical member for each sheet in accordance with the length of the sheet. At the start of each feeding cycle a detent on the pawl urges the cylindrical member in the direction opposite its feeding rotation for a short distance. As a result, the lowermost sheet is initially slightly buckled, freeing it from the next adjacent sheet and insuring single sheet feed.

United States Patent [191 Aronson [111 3,851,871 [451 Dec. 3, 1974 HIGHSPEED SHEET FEEDING APPARATUS Filed: Dec. 10, 1973 Appl. No.: 423,144

[56] References Cited UNITED STATES PATENTS l/1969 Konazewski 271/1002/1973 Comstock 3/1974 Schilpf 271/100 Primary Examiner-Even C. BlunkAssistant Examiner-James W. Miller 57 ABSTRACT A high speed sheetfeeding apparatus in which the lowermost sheet of a stack is propelledfrom the stack by a rotating perforate cylindrical member connected to asource of vacuum. A pawl actuated by an adjustable cam governs theamount of rotation of the cylindrical member for each sheet inaccordance with the length of the sheet. At the start of each feedingcycle a detent on the pawl urges the cylindrical member in the directionopposite its feeding rotation for a short distance. As a result, thelowermost sheet is initially slightly buckled, freeing it from the nextadjacent sheet and insuring single sheet feed.

9 Claims, 4 Drawing Figures PATENHL BEE mm SHEET 10F 3 PATENIEL BEE31974 SHEE? 2 BF 3 PAIENTEL DEB EH 3 0F 3 HIGH SPEED SHEET FEEDINGAPPARATUS BACKGROUND OF THE DISCLOSURE It is well-known to feed sheetsof material such as paper, cardboard and the like from the bottom of astack by means of oscillating cylinders and suckers connected to asource of vacuum. Examples of such devices are' to be found in US. Pat.Nos. 2,704,209 issued to J. Halahan et al Mar. 15, 1955; 2,770,458issued to J. Halahan et al. Nov. 13, 1956; 2,859,964 issued to T. F.Aronson et a1. Nov. 1 1, 1958 and others. Such prior art devices,however, were subject to certain limitations as to speed of operation,dependability of single sheet feed, the necessity for valving, thicknessof material which could be fed etc.

Accordingly, it is an object of the present invention to provide a sheetfeeding apparatus which can operate at high speed on a wide variety ofsheet materials.

Another object is to provide a sheet feeding apparatus in which thesheet being fed is under positive control for the major portion of itslength.

A further object is to provide a positive separation of the bottom sheetfrom the next adjacent sheet at the start of each feed cycle so thatmore than one sheet is not fed out at one time.

An object of the present invention is to prevent damage to the sheetbeing fed by reason of stresses set up in the sheet by the feedmechanism.

Still another object of the present invention is to provide a sheetfeeding apparatus which lends itself to easy adjustment for differentlengths of material.

SUMMARY The sheet feeding apparatus of the present invention includes aninclined or horizontal sheet receiving hopper having an opening thereinthrough which the lowermost sheets can be drawn and fed in a desiredpath. A hollow, cylindrical member connected to a constant source ofvacuum and having a series of openings therein is disposed in contactwith a portion of the lowermost sheet which overlies the hopper opening.A circular plate having a plurality of pins extending outwardly thereofis carried upon a shaft upon which the cylindrical member is mounted.The amount of rotation of the cylindrical member and therefore theamount of feed imparted to each sheet is controlled by a cam actuatedpawl which is preset to permit one or more pins to be moved past thepawl by a suitable power source during each cycle.

At the start of each sheet feed cycle, a detent on the pawl toothengages the pin upon which it has come to rest at the end of the lastcycle. The shape of the detent is such that is imparts a small motion tothe cylindrical member opposite the direction of feed. This small motioncauses the lowermost sheet which is held to the cylindrical member bythe vacuum to buckle slightly thereby releasing it from the nextadjacent sheet so that only one sheet will be fed by the apparatus ineach cycle.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings forming parthereof similar parts have been given the same reference numerals, inwhich drawings;

FIG. 1 is a view in side elevation of a complete embodiment of thepresent invention.

FIG. 2 is a view taken on line 2 2 in FIG. I looking in the direction ofthe arrows, with certain elements somewhat laterally displaced for thesake of clarity.

FIG. 3 is a fragmentary cross-sectional view taken on line 3-3 in FIG. 2looking in the direction of the arrows with certain parts shown indashed lines.

FIG. 4 is a fragmentary cross-sectional view on an enlarged scalesimilar to FIG. 3 showing the manner in which the lowermost sheet isslightly buckled to free it from the next adjacent sheet.

GENERAL DESCRIPTION Referring to the drawings and particularly to FIGS.1 and 2, there is shown a base .10 having spaced up standing side platesll, 12 secured thereto. A drive shaft 13 coupled toa source ofrotarypower such as an electric motor (not shown) extends across the sheetfeeding apparatus and is journaled in each of the side gated slot 21 toreceive a pin 22 carried by the first plate 23 of a clutch 24. A smallspur gear 25 is incorporated into the other plate 26 of the clutch 24.The spur gear is in mesh with a drive gear 27 pinned to the drive shaft13. Adjustability is provided for theclutch 24 by means of the nuts 28,29 threaded on to the end of shaft 18.

A hollow cylindrical sheet feed member 30, having a plurality of equallyspaced slots 31 therein is secured to the inner end 32 of the drivenshaft l8'and is rotated therewith. The sheet feed member 30 also ridesupon a hollow cylindrical vacuum chamber 33 which is freely fittedwithin the sheet feed member 30. The vacuum chamber 33 is secured to theinner end of the hollow shaft 15 which is connected to a constant sourceof vacuum (not shown). A single row of spaced openings 34 is provided inthe vacuum chamber 33 so that the slots 31 in the sheet feed memberwhich are brought into register with the .vacuum chamber slots 34provide communication with the vacuum within the chamber 33.

As shown in FIG. 1, a sheet receiving rack or hopper 35 is provided inthe sheet feeding apparatus and is adapted to hold a stack of individualsheets 36. The hopper consists of a bottom support member 37 andupstanding walls 38 adjustably secured to the bottom support 37 toaccommodate sheets of different sizes. While the hopper 35 has beenshown with the bottom support 37 on an incline, it will be understoodthat a horizontal disposition of the bottom support 37 is within thepurview of the present invention.

The bottom support 37 for the stack of sheets 36 is provided with anopening or window 39 into which the sheet feed member 33 extends andthrough which the lowermost sheet can be pulled by the sheet feedmemher.

A plurality of spaced pins 40 are carried by the first plate of theclutch 23 and extend outwardly thereof as shown in FIG. 2. Each pin 40is engagable by a pawl 41 disposed in the pins path of travel. The pawl41 is formed at one end of a bell crank lever 42 pivotally secured at 43to the side plate 11. The bell crank lever 42 is normally urged in thedirection of the pins 40 by coil spring 44. A roller 45 is carried bythe bell crank lever 42 and extends outwardly thereof in the path of anadjustable cam 46.

The cam 46, best shown in FIGS. 1, 3 and 4 consists of two cam discs 47,48 each having a lobe 49, 50. By rotating the discs 47, 48 with respectto each other, the length of the cam lobe may be adjusted. The cam 46,is secured to the drive shaft 13 and rotates with it. As the cam lobeengages the roller 45, it rotates the bell crank lever 42 swinging thepawl 41 away from the pins 40. When the pin 40 engaged by the pawl 41 isreleased the first clutch plate 23 is free to rotate and turn the sheetfeed member 30.

it will be seen from an examination of FIGS. 1, 3 and 4, that the end ofthe pawl 41 is provided with a depending detent 51 which partiallyencircles the pin 40 engaged by the pawl. This causes the initialmovement of the clutch 23 and consequently the sheet feed member to bein a direction counter to the sheet feed path.

From the foregoing description the operation of the sheet feed apparatuswill be understood to be as follows:

With a stack of individual sheets 36 within the hopper 35, the source ofvacuum activated, and the source of rotary power started; one of theslots 31 in the sheet feed member 30 which is in register with theopenings 34 will cause the vacuum to pull the leading portion of thelowermost sheet in the stack through the window 39 in the bottom support37 as shown in FIG. 3 at 52. The leading portion of the sheet willoverlie the slots 31. As the cam 46 is rotated by the drive shaft 13, itwill urge the pawl 41 away from the pin 40. As best shown in FIG. 4, themotion of the pawl 41 first causes the detent 51 to impart a reversemovement of the pin 40 resulting in a small counter rotation of thesheet feed member 30 and a small buckling of the sheet held thereby asshown at 53. This buckling frees the lowermost sheet from the nextadjacent sheet and insures single sheet feeding even at high speeds.

The pawl 41 is held out of the path of the pins for an intervaldepending upon the adjustment of the cam lobes 49, 50 which adjustmentis related to the length of the sheet being fed. At the end of each feedcycle the roller 45 rides off the cam lobes and the coil spring urgesthe pawl 41 into the path of the pins 40. The feed cycle is thencompleted.

It will be noted that as successive slots 31 reach the openings 34 inthe vacuum chamber 33 the sheet being fed will receive additionalpropulsion thereby, aiding in pulling it from the stack. reducingstresses within the sheet and keeping the sheet under control as it isbeing fed.

To further control the sheet as it is being fed out of the stack, thereis provided a spaced roller assembly 54 mounted upon a transverse shaft55. The shaft 55 is carried at each end by the side plates 11, 12 androckably supports two spaced arms 56. The arms 56 extend in a directionparallel to the line of travel of the sheets. The inner ends of the arms56 extend over the sheet feed member 30 as shown in FIG. 3 and are transversely bored and provided with bearings 57 as shown in FIG. 2. A rollershaft 58 is freely received withing the bearings 57. Two spaced rollers59 are carried by and secured to the roller shaft 58. The outer surfacesof the rollers 59 are urged against the races of two spaced bearings 60,61 which are carried upon the inner ends of hollow shafts 14, 15 on eachside of the sheet feed member 30. A coil spring 62, best shown is FIG.3, on each of the outer ends of the arms 56 serves to urge the rollers59 in the direction of the bearings 60, 61.

It will be seen that sheets being fed out of the stack will be ledbetween the rollers 59 and the surfaces of bearings 61 and directedalong the proper line of travel. Rotary motion is imparted to therollers 59 by means of a stub shaft 63 having a spur gear 64 at itsouter end in mesh with the spur gear 25 of the clutch 24 and a coupling65 at its inner end engaging a complimentary coupling 50 on the rollershaft 58.

After the fed sheet leaves the sheet feed member 30 and rollers 59 it isfurther directed out of the sheet feeding apparatus by a guide plate 66and one or more pairs of pinch rollers 67, 67a.

The pinch rollers 67, 670 are best shown in FIGS. 1, 2 and 3 and consistof a lower set of spaced rollers 67a secured to a transverse shaft 68which is freely journaled at each end to the side plates 11, 12. One endof the shaft 68 extends beyond side plate 11 to provide a stub shaft 69to which a driven gear 71 is secured. The spur gear 71 is in mesh withgear 27 on the drive shaft 13. The rollers 67a are thus driven by therotary motion of the drive shaft 13.

The upper pinch rollers 67 as best shown in FIG. 3 are freely journaledupon shafts 72 extending outwardly of carriers 73. The carriers areswingably held by stub shafts 74 secured to the side plates 11, 12, andare urged in the direction of the bottom pinch rollers 67a by small coilsprings 75. The upper pinch rollers 67 are thus in yielding contact withthe lower pinch rollers 67a and the sheets are fed therebetween.

As a result of the gear train which is in mesh with the drive gear 27 nostresses are set up in the sheets being fed. in addition, the singledirection of rotation of the feed member 30 (other than the initialshort reverse motion to release the bottom-most sheet) and thecontinuing control of the sheet as it is being fed makes it possible tofeed relatively thin sheets at high speeds. There is no stress set upwithin the sheet, as for example, by pinch rollers pulling the sheet inone direction while a vacuum feed member is pulling the sheet inopposite direction.

From the foregoing it will be seen that there has been provided a sheetfeeding apparatus, capable of operating at high speeds and on a widevariety of sheet sizes and thicknesses.

I claim:

1. A high speed sheet feeding apparatus for leading individual sheetsout of a stack of sheets along a desired path comprising a base plate,spaced upstanding side plates secured to the base plate. opposed firstand second shafts carried by the side plates at their outer ends andextending inwardly of the side plates toward each other, a clutch membercoupled to the first shaft, means including a drive shaft to impartrotary motion to the clutch member, a hollow perforate cylindrical sheetfeed member coaxially carried between the first and second shafts, ahollow cylindrical vacuum chamber within the feed member, said vacuumchamber having at least one slot therein in communication with theinterior thereof and a constant source of vacuum attached to said vacuumchamber, a rotatable plate operatively coupled to the sheet feed member,a plurality of spaced pins carried by the plate and extending outwardlythereof, a pawl swingably disposed in the path of the pins to normallyrestrain the pins, a cam adjacent said pawl to swing the pawl into andout of engagement with the pins, a hopper to receive the stack of sheetshaving a bottom support and upstanding walls, said bottom support beingprovided with an opening therein through which the lowermost sheet canbe extracted, said bottom support being non-vertically disposed and withthe lowermost sheet in contact with the sheet feed member through thebottom memberopening, rollers to guide the sheet as it is being fed bythe sheet feed member, and a depending detent partially encircling thepin upon which it is brought to rest whereby when the pawl is initiallyreleased from the pin, the detent will impart a short counter revolutionto the sheet feed member.

2. Apparatus according to claim 1 in which the first and second shaftsare hollow, an elongated driven shaft is disposed within the first shaftsecured at its outer portion to the clutch member and at its inner endto the sheet feed member and the vacuum source is connected to thesecond hollow shaft.

3. Apparatus according to claim 2 in which the clutch member includesthe rotatable plate operatively coupled to the elongated driven shaftand an inner second plate for driving engagement with the first plate.

4. Apparatus according to claim 2 in which the feed member is freelycarried upon the vacuum chamber and grasps the sheet along that portionof the feed member opening in register with the vacuum chamber slots.

5. Apparatus according to claim 2 in which the pawl is in the form of abell crank lever having a roller thereon disposed in the path of thecam, and a spring is coupled to the pawl to yieldably urge it in thedirection of the pins.

6. Apparatus according to claim 2 in which the rollers include spacedrollers on each side of the feed member, spaced yieldable rollerscarried upon a transverse shaft, driven by the power source and ridingupon the feed member rollers and at least one pair of pinch rollerstransversely carried between the side plates to receive sheets comingfrom the feed member.

7. Apparatus according to claim 1 in which the cam comprises a first anda second disc carried upon the drive shaft, a cam lobe on each of thediscs disposed in the path of the pawl bell crank lever and means toadjust the lobes with respect to each other to increase or decrease thedwell of the pawl bell crank lever.

8. A high speed sheet feeding apparatus comprising a frame, opposedfirst and second shafts carried by the frame at their outer ends andextending inwardly toward each other, clutch means coupled to the firstshaft, means including a drive shaft to impart rotary motion to theclutch member, a hollow perforate cylindrical sheet feed member carriedbetween the first and second shafts, a hollow cylindrical vacuum chamberwithin the feed member, said vacuum chamber having at least one slottherein, a source of vacuum in communication with the interior of saidvacuum chamber, a rotatable plate operatively coupled to the sheet feedmember, a plurality of spaced pins carried by the plate and extendingoutwardly thereof, a pawl swingably disposed in the path of the pins tonormally restrain at least one of the pins, cam means to swing the pawlinto and out of engagement with the pins, a non-vertically disposedhopper to receive the stack of sheets, a bottom support for said hopper,said bottom support being provided with an opening therein through whichthe lowermost sheet can be extracted, said lowermost sheet adapwd qs nast he .shsstfizsd msmbsr fihrqa the bott orn member opening, and 21depending detent partially encircling the pin upon which it is broughtto rest whereby when the pawl is initially released from the pin, thedetent will impart a short counter revolution to the sheet feed member.

9. A high speed sheet feeding apparatus comprising a hollow cylindricalvacuum chamber having atleast one slot in the wall thereof communicatingbetween the exterior and interior thereof, a hollow perforatecylindrical sheet feed member rotatably carried upon the vacuum chamber,hopper means for supporting a stack of sheets adjacent the sheet feedmember, drive means for rotating the sheet feed member so as to bringsuccessive perforations in register with the vacuum chamber slots,clutch means interconnecting the drive means and the sheet feed member,a plate operatively coupled to the clutch means, a plurality ofoutwardly extending pins on said plate, a swingable pawl disposed in thepath of the pins, a detent on said pawl adapted to overlie at least oneof said pins when it is brought to rest and cam means to bring the pawlinto and out of engagement with the pins to interrupt the sheet feedingappa-

1. A high speed sheet feeding apparatus for leading individual sheetsout of a stack of sheets along a desired path comprising a base plate,spaced upstanding side plates secured to the base plate, opposed firstand second shafts carried by the side plates at their outer ends andextending inwardly of the side plates toward each other, a clutch membercoupled to the first shaft, means including a drive shaft to impartrotary motion to the clutch member, a hollow perforate cylindrical sheetfeed member coaxially carried between the first and second shafts, ahollow cylindrical vacuum chamber within the feed member, said vacuumchamber having at least one slot therein in communication with theinterior thereof and a constant source of vacuum attached to said vacuumchamber, a rotatable plate operatively coupled to the sheet feed member,a plurality of spaced pins carried by the plate and extending outwardlythereof, a pawl swingably disposed in the path of the pins to normallyrestrain the pins, a cam adjacent said pawl to swing the pawl into andout of engagement with the pins, a hopper to receive the stack of sheetshaving a bottom support and upstanding walls, said bottom support beingprovided with an opening therein through which the lowermost sheet canbe extracted, said bottom support being non-vertically disposed and withthe lowermost sheet in contact with the sheet feed member through thebottom member opening, rollers to guide the sheet as it is being fed bythe sheet feed member, and a depending detent partially encircling thepin upon which it is brought to rest whereby when the pawl is initiallyreleased from the pin, the detent will impart a short counter revolutionto the sheet feed member.
 2. Apparatus according to claim 1 in which thefirst and second shafts are hollow, an elongated driven shaft isdisposed within the first shaft secured at its outer portion to theclutch member and at its inner end to the sheet feed member and thevacuum source is connected to the second hollow shaft.
 3. Apparatusaccording to claim 2 in which the clutch member includes the rotatableplate operatively coupled to the elongated driven shaft and an innersecond plate for driving engagement with the first plate.
 4. Apparatusaccording to claim 2 in which the feed member is freely carried upon thevacuum chAmber and grasps the sheet along that portion of the feedmember opening in register with the vacuum chamber slots.
 5. Apparatusaccording to claim 2 in which the pawl is in the form of a bell cranklever having a roller thereon disposed in the path of the cam, and aspring is coupled to the pawl to yieldably urge it in the direction ofthe pins.
 6. Apparatus according to claim 2 in which the rollers includespaced rollers on each side of the feed member, spaced yieldable rollerscarried upon a transverse shaft, driven by the power source and ridingupon the feed member rollers and at least one pair of pinch rollerstransversely carried between the side plates to receive sheets comingfrom the feed member.
 7. Apparatus according to claim 1 in which the camcomprises a first and a second disc carried upon the drive shaft, a camlobe on each of the discs disposed in the path of the pawl bell cranklever and means to adjust the lobes with respect to each other toincrease or decrease the dwell of the pawl bell crank lever.
 8. A highspeed sheet feeding apparatus comprising a frame, opposed first andsecond shafts carried by the frame at their outer ends and extendinginwardly toward each other, clutch means coupled to the first shaft,means including a drive shaft to impart rotary motion to the clutchmember, a hollow perforate cylindrical sheet feed member carried betweenthe first and second shafts, a hollow cylindrical vacuum chamber withinthe feed member, said vacuum chamber having at least one slot therein, asource of vacuum in communication with the interior of said vacuumchamber, a rotatable plate operatively coupled to the sheet feed member,a plurality of spaced pins carried by the plate and extending outwardlythereof, a pawl swingably disposed in the path of the pins to normallyrestrain at least one of the pins, cam means to swing the pawl into andout of engagement with the pins, a non-vertically disposed hopper toreceive the stack of sheets, a bottom support for said hopper, saidbottom support being provided with an opening therein through which thelowermost sheet can be extracted, said lowermost sheet adopted tocontact the sheet feed member through the bottom member opening, and adepending detent partially encircling the pin upon which it is broughtto rest whereby when the pawl is initially released from the pin, thedetent will impart a short counter revolution to the sheet feed member.9. A high speed sheet feeding apparatus comprising a hollow cylindricalvacuum chamber having at least one slot in the wall thereofcommunicating between the exterior and interior thereof, a hollowperforate cylindrical sheet feed member rotatably carried upon thevacuum chamber, hopper means for supporting a stack of sheets adjacentthe sheet feed member, drive means for rotating the sheet feed member soas to bring successive perforations in register with the vacuum chamberslots, clutch means interconnecting the drive means and the sheet feedmember, a plate operatively coupled to the clutch means, a plurality ofoutwardly extending pins on said plate, a swingable pawl disposed in thepath of the pins, a detent on said pawl adapted to overlie at least oneof said pins when it is brought to rest and cam means to bring the pawlinto and out of engagement with the pins to interrupt the sheet feedingapparatus.